Waste Aluminum Application as Energy Valorization for Hydrogen Fuel Cells for Mobile Low Power Machines Applications

This article proposes a new model of power supply for mobile low power machines applications, between 10 W and 30 W, such as radio-controlled (RC) electric cars. This power supply is based on general hydrogen from residual aluminum and water with NaOH, so it is proposed energy valorization of aluminum waste. In the present research, a theoretical model allows us to predict the requested aluminum surface and the required flow of hydrogen has been developed, also considering, in addition to the geometry and purity of the material, two key variables as the temperature and the molarity of the alkaline solution used in the hydrogen production process. Focusing on hydrogen production, isopropyl alcohol plays a key role in the reactor’s fuel cell vehicle as it filters out NaOH particles and maintains a constant flow of hydrogen for the operation of the machine, keeping the reactor temperature controlled. Finally, a comparison of the theoretical and experimental data has been used to validate the developed model using aluminum sheets from ring cans to generate hydrogen, which will be used as a source of hydrogen in a power fuel cell of an RC car. Finally, the manuscript shows the parts of the vehicle’s powertrain, its behavior, and mode of operation.

Effect of Residual Aluminum Thickness on Microstructure and Strength of Friction Stir Spot Welded Aluminum Alloy/Copper Lap Joint

Dissimilar metal lap joining of A5052 aluminum alloy plate and C1100 pure copper plate was performed by using friction stir spot welding. The rotating welding tool, which was composed of a probe part and a shoulder part, was plunged from the aluminum alloy plate which was overlapped on the copper plate, and residual aluminum alloy thickness under the probe part of the welding tool after plunging of the welding tool was controlled in the range from 0 mm to 0.4 mm. The strength of the welding interface was evaluated by using tensile-shear test. Microstructure of the welding interface was examined by using an optical microscope and a field emission scanning electron microscope. The welding was achieved at the residual aluminum alloy thickness under the probe part of the welding tool below 0.3 mm. The welded area was formed at aluminum alloy/copper interface located under the probe part of the welding tool, and its width increased with decreasing the residual aluminum alloy thickness. A characteristic laminate structure was produced in the copper matrix near the welding interface. In the joint fabricated at the residual aluminum alloy thickness below 0.1 mm, hook of Cu was formed at edge of the welded area. The fracture did not occur at the welding interface. A remarkable improvement in strength was observed in the joint fabricated at the residual aluminum alloy thickness below 0.1 mm. The formation of laminate structure and hook is considered to result in joint strength improvement.

Characterization of particles and their relation with residual aluminum in water treated with pulsating floc blanket clarifiers and conventional clariflocculators using PACl

A pulsating floc blanket clarifier (PFBC) employing cyclic contractions and rarefactions to a bed of densely concentrated suspension of flocculated particles in fluidized state, was compared with conventional clariflocculator (CC) at pilot scale (8,000 L/day) in continuous mode of operation. For influent turbidity varied from 2 to 20 NTU, coagulation-flocculation behavior exhibited under the two fundamentally different treatment processes with PACl influenced inter-related performance parameters. The residual turbidity was found lower by 74%, flocs and fine colloids in suspension larger by 73 and 75% respectively, and the total and dissolved residual aluminum lower by 50 and 49% respectively on average for PFBC compared to CC. Particulate form comprised major fraction (≈72%) of total residual aluminum for both. PFBC abetted formation of a more consolidated floc structure which rendered the shape, size and morphology such that the settling velocity was 50% to 410% higher than that of the CC flocs. Reaction-limited aggregation (RLA) process and inter-particle bridging were dominant and the resulting floc structure and its formation mechanism have been presented.

Estimation of the effectiveness of ozone use in the purification of heavily contaminated water supply sources

Источники питьевого водоснабжения (реки Великая, Волга, Вычегда, Которосль, Лименда, Солда, Северная Двина, Томь и Тура) характеризуются повышенным содержанием органических соединений природного и антропогенного происхождения. Традиционная технология двухступенчатого осветления воды коагулированием в данном случае по своей эффективности не соответствует качеству воды источника, в результате по некоторым показателям питьевая вода периодически не отвечает современным требованиям стандарта. Особенно сложно обеспечивать в питьевой воде предельно допустимые концентрации органических веществ, а также соединений железа, марганца и остаточного алюминия. Для очистки такой воды были изучены дополнительные методы окисления и сорбции. Результаты исследований показали, что предварительное озонирование речной воды и (или) постозонирование воды после фильтров станции водоподготовки повышают эффективность очистки по цветности, мутности, удалению соединений железа и марганца, уменьшают концентрацию остаточного алюминия, улучшают органолептические показатели. Сорбционная очистка с озонированием существенно улучшает качество очищенной воды и позволяет обеспечить допустимый уровень содержания органических загрязнителей в питьевой воде. Sources of drinking water supply (the Velikaia, Volga, Vychegda, Kotorosl’, Limenda, Solda, Severnaia Dvina, Tom’ and Tura rivers) are characterized by increased concentrations of organic compounds of natural and anthropogenic origin. The traditional technology of two-stage water clarification by coagulation in terms of the efficiency, in this case, is not applicable to the quality of the source water; as a result, by some indicators, drinking water periodically does not meet the current standard requirements. It is especially difficult to ensure the permissible maximum concentrations of organic substances in drinking water, as well as of compounds of iron, manganese and residual aluminum. To provide for the purification of such water, additional oxidation and sorption methods have been studied. The research results showed that preliminary ozonation of river water and (or) post-ozonation of water after filtration at a water treatment plant provide for increasing the efficiency of purification in terms of color, turbidity, removal of iron and manganese compounds; for reducing the concentration of residual aluminum, and improving the organoleptic characteristics. Sorption with ozonation significantly improves the quality of treated water and allows to ensure the permissible level of organic pollutants in drinking water.

Removal of color and turbidity in sugarcane juice treated by electrocoagulation with aluminum electrodes

The liming (Ca(OH)2 addition) and sulfitation (HSO3- addition) is the conventional treatment for purification of sugarcane juice (SCJ) in sugar cane mills to crystal sugar production. Although, the sulfite has been associated to human health problems, this industrial step kept untouchable or few studies have been made to change this scenery. This work aimed to evaluate the variables which influence the electrocoagulation performance on the SCJ purification as a sulfur-free crystal sugar process. A fractional factorial design with the surface response methodology was used to evaluate the influence of voltage, pH, soluble solids total (Brix), temperature and distance between the electrodes in the electrocoagulation process. The outputs were turbidity, juice color, sucrose contents (as pol%juice) and Reducing Sugars (RS). Residual aluminum was analyzed by voltammetry to control de aluminum releasing into the treated juice. The electrocoagulation reduced color and turbidity, in special at low pH (2.5), highest voltage (25 V) and minimal distance of electrode (1.0 cm). Although in this conditions, sucrose was converted into RS indicating partial hydrolysis. In this work, the most part of residual aluminum went to floated and precipitated phases (76.8% and 18.1%, respectively), whereas only 5.1% remained in the SCJ clarified. Electrocoagulation/electroflotation proved to be a potential technique as a substitute for sulfitation in SJC treatment, which ensures the production of safe food for humans.

Fate and fractionation of aluminum in a full-scale Al-based drinking water treatment plant

Residual aluminum in drinking water is widely concerning due to its potentially harmful effect on human health and drinking water distribution systems. The fate and fractionation of aluminum and the factors influencing residual aluminum in a full-scale Al-based drinking water treatment plant (DWTP) was presented in Jiaxing, China. The results showed that treated water residual aluminum concentration was less than 0.1 mg/L regardless of the seasonal change of raw water aluminum concentration. The addition of secondary flocculation had a negligible influence on treated water residual aluminum concentration due to the efficient removal of particulate aluminum by sand filter. Residual aluminum concentration of treated water was lower (mean 0.037 mg/L) in summer (average water temperature was 29 °C) than that (mean 0.067 mg/L) in winter (average water temperature was 16 °C). Significant positive relationships between particulate aluminum concentration and particle counts, as well as the total aluminum concentration of treated water and turbidity, were found. Those relationships provided the possibility to estimate residual aluminum concentration by monitoring particle counts and turbidity.

Application of Composite Pre-Polymerized Coagulants for the Treatment of High-Strength Industrial Wastewaters

The aim of this study was the investigation of alternative pre-polymerized coagulants for the treatment of high-strength industrial wastewaters, such as those created by tanneries, or by yeast production industries. The novel inorganic composite coagulant examined in this study (as well as variations of it) was denoted as PSiFAC1.5-10-15. The contribution of a typical polyelectrolyte to improve the effectiveness of the coagulation/flocculation (C/F) process was additionally studied, either by adding it separately (i.e., as a flocculant aid) or by co-polymerizing it within the structure of inorganic coagulant (denoted as PAPEFAC1.5-10-15). It was found that the PSiFAC1.5:10:15 coagulant, either with or without the addition of polyelectrolyte, can provide better efficiency for the C/F process than the conventional coagulants. For example, the addition of 80 mg Al/L in yeast production wastewater samples resulted in a 56% reduction of COD, 40% of turbidity, and 43% of phosphates, regarding the pre-treated anaerobically wastewater samples and reduced by an extra 22%, 14%, and 38% for the pre-treated anaerobically plus aerobically wastewater samples, respectively. The residual aluminum concentration in the treated wastewaters was found to be below the legislation limit of 200 μg Al/L. The characterization of coagulants showed the relatively higher Al13 content of 51% and 43% for the cases of PSiFAC1.5-10-15 and PAPEFAC1.5-10-15, respectively, accompanied by the high zeta-potential measurements (50.5 and 39.5 mV).

Effect of Alkalinity on Catalytic Activity of Iron–Manganese Co-Oxide in Removing Ammonium and Manganese: Performance and Mechanism

In this study, a pilot-scale experimental filter system was used to investigate the effect of bicarbonate alkalinity on the activity of an Fe–Mn co-oxide for ammonium and manganese removal from surface water. The results showed that an increase in alkalinity to 150 mg/L (calculated as CaCO3) by the addition of NaHCO3 significantly promoted the activity of the Fe–Mn co-oxide. The ammonium and manganese removal efficiencies of the Fe–Mn co-oxide increased from 40% to 95% and 85% to 100%, respectively. After NaHCO3 was no longer added, the activity of the filter column remained. Moreover, pH (7.4–8.0) and temperature (12.0–16.0 °C) were not the main factors affecting the activity of the filter, and had no significant effect on the activity of the filter. Further characterization analysis of the Fe–Mn co-oxide filter film showed that after alkalinity was increased, the accumulation of aluminum on the filter media surface decreased from 3.55% to 0.16% and the oxide functional groups changed. This was due to the action of bicarbonate and the residual aluminum salt coagulant in the filter, which caused the loss of Al from the surface of the filter media and weakened the influence of the aluminum salt coagulant on the activity of the Fe–Mn co-oxide; hence, the activity was recovered.

PURIFICATION OF OPEN PIT WATER OF PJSC «SEVERALMAZ» FROM DISPERSE PARTICLES OF CLAYEY MINERAL SAPONITE BY THE COAGULATION METHOD

In the article, the process of water purification mainly from suspended particles of clay mineral saponite is considered. Those particles are formed during the process of diamond mining in the quarry water of M.V. Lomonosov Mining and Processing Plant owned by PJSC «Severalmaz». The scheme of the existing technology of sedimentation of suspended particles using the acoustic method is shown. Using the granulometry method the size of suspended particles in free volume was studied, and the sedimentation rate of suspended substances was calculated using Stokes' formula. The mineral composition of suspended particles in the quarry water is determined using Х-ray phase analysis. Calculations of the sedimentation rates of suspended particles are given for aluminum sulfate – traditionally used in water clarification – and for calcium-aluminosilicate reagent developed when taking into account the mineral composition. The results of measurements of pH of the clarified water, the content of residual aluminum, and the indicator of turbidity of the water are shown